root / posix-aio-compat.c @ 0497d2f4
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/*
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* QEMU posix-aio emulation
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*
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* Copyright IBM, Corp. 2008
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include <pthread.h> |
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#include <unistd.h> |
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#include <errno.h> |
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#include <time.h> |
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#include <string.h> |
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#include <stdlib.h> |
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#include <stdio.h> |
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#include "osdep.h" |
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#include "posix-aio-compat.h" |
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static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
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static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
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static pthread_t thread_id;
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static pthread_attr_t attr;
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static int max_threads = 64; |
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static int cur_threads = 0; |
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static int idle_threads = 0; |
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static TAILQ_HEAD(, qemu_paiocb) request_list;
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static void die2(int err, const char *what) |
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{ |
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fprintf(stderr, "%s failed: %s\n", what, strerror(err));
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abort(); |
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} |
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static void die(const char *what) |
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{ |
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die2(errno, what); |
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} |
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static void mutex_lock(pthread_mutex_t *mutex) |
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{ |
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int ret = pthread_mutex_lock(mutex);
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if (ret) die2(ret, "pthread_mutex_lock"); |
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} |
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static void mutex_unlock(pthread_mutex_t *mutex) |
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{ |
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int ret = pthread_mutex_unlock(mutex);
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if (ret) die2(ret, "pthread_mutex_unlock"); |
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} |
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static int cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, |
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struct timespec *ts)
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{ |
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int ret = pthread_cond_timedwait(cond, mutex, ts);
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if (ret && ret != ETIMEDOUT) die2(ret, "pthread_cond_timedwait"); |
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return ret;
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} |
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static void cond_signal(pthread_cond_t *cond) |
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{ |
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int ret = pthread_cond_signal(cond);
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if (ret) die2(ret, "pthread_cond_signal"); |
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} |
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static void thread_create(pthread_t *thread, pthread_attr_t *attr, |
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void *(*start_routine)(void*), void *arg) |
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{ |
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int ret = pthread_create(thread, attr, start_routine, arg);
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if (ret) die2(ret, "pthread_create"); |
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} |
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static void *aio_thread(void *unused) |
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{ |
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pid_t pid; |
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sigset_t set; |
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pid = getpid(); |
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/* block all signals */
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if (sigfillset(&set)) die("sigfillset"); |
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if (sigprocmask(SIG_BLOCK, &set, NULL)) die("sigprocmask"); |
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while (1) { |
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struct qemu_paiocb *aiocb;
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size_t offset; |
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int ret = 0; |
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qemu_timeval tv; |
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struct timespec ts;
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qemu_gettimeofday(&tv); |
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ts.tv_sec = tv.tv_sec + 10;
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ts.tv_nsec = 0;
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mutex_lock(&lock); |
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while (TAILQ_EMPTY(&request_list) &&
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!(ret == ETIMEDOUT)) { |
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ret = cond_timedwait(&cond, &lock, &ts); |
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} |
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if (TAILQ_EMPTY(&request_list))
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break;
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aiocb = TAILQ_FIRST(&request_list); |
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TAILQ_REMOVE(&request_list, aiocb, node); |
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offset = 0;
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aiocb->active = 1;
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idle_threads--; |
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mutex_unlock(&lock); |
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while (offset < aiocb->aio_nbytes) {
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ssize_t len; |
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if (aiocb->is_write)
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len = pwrite(aiocb->aio_fildes, |
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(const char *)aiocb->aio_buf + offset, |
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aiocb->aio_nbytes - offset, |
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aiocb->aio_offset + offset); |
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else
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len = pread(aiocb->aio_fildes, |
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(char *)aiocb->aio_buf + offset,
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aiocb->aio_nbytes - offset, |
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aiocb->aio_offset + offset); |
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if (len == -1 && errno == EINTR) |
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continue;
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else if (len == -1) { |
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offset = -errno; |
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break;
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} else if (len == 0) |
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break;
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offset += len; |
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} |
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mutex_lock(&lock); |
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aiocb->ret = offset; |
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idle_threads++; |
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mutex_unlock(&lock); |
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if (kill(pid, aiocb->ev_signo)) die("kill failed"); |
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} |
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idle_threads--; |
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cur_threads--; |
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mutex_unlock(&lock); |
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return NULL; |
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} |
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static void spawn_thread(void) |
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{ |
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cur_threads++; |
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idle_threads++; |
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thread_create(&thread_id, &attr, aio_thread, NULL);
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} |
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int qemu_paio_init(struct qemu_paioinit *aioinit) |
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{ |
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int ret;
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ret = pthread_attr_init(&attr); |
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if (ret) die2(ret, "pthread_attr_init"); |
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ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); |
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if (ret) die2(ret, "pthread_attr_setdetachstate"); |
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TAILQ_INIT(&request_list); |
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return 0; |
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} |
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static int qemu_paio_submit(struct qemu_paiocb *aiocb, int is_write) |
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{ |
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aiocb->is_write = is_write; |
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aiocb->ret = -EINPROGRESS; |
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aiocb->active = 0;
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mutex_lock(&lock); |
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if (idle_threads == 0 && cur_threads < max_threads) |
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spawn_thread(); |
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TAILQ_INSERT_TAIL(&request_list, aiocb, node); |
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mutex_unlock(&lock); |
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cond_signal(&cond); |
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return 0; |
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} |
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int qemu_paio_read(struct qemu_paiocb *aiocb) |
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{ |
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return qemu_paio_submit(aiocb, 0); |
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} |
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int qemu_paio_write(struct qemu_paiocb *aiocb) |
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{ |
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return qemu_paio_submit(aiocb, 1); |
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} |
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ssize_t qemu_paio_return(struct qemu_paiocb *aiocb)
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{ |
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ssize_t ret; |
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mutex_lock(&lock); |
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ret = aiocb->ret; |
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mutex_unlock(&lock); |
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return ret;
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} |
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int qemu_paio_error(struct qemu_paiocb *aiocb) |
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{ |
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ssize_t ret = qemu_paio_return(aiocb); |
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if (ret < 0) |
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ret = -ret; |
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else
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ret = 0;
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return ret;
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} |
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int qemu_paio_cancel(int fd, struct qemu_paiocb *aiocb) |
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{ |
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int ret;
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mutex_lock(&lock); |
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if (!aiocb->active) {
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TAILQ_REMOVE(&request_list, aiocb, node); |
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aiocb->ret = -ECANCELED; |
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ret = QEMU_PAIO_CANCELED; |
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} else if (aiocb->ret == -EINPROGRESS) |
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ret = QEMU_PAIO_NOTCANCELED; |
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else
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ret = QEMU_PAIO_ALLDONE; |
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mutex_unlock(&lock); |
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return ret;
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} |